Swivel knife



J. F. BUNKER Sept. 25, 1951 SWIVEL KNIFE Filed March l, 1949 FIG. 5.

INVENTOR. .JOSEPH FARRIN BUNKER Patented Sept. 25, 1951 UNITED STATESPATENT OFFICE SWIVEL KNIFE Joseph Farrin Bunker, Rockville Centre, N. Y.Y

Application March 1, 1949, Serial No. 78,967

' v2. Claims.

This invention relates to a cutting instrument, more particularly, to aninstrument for use in the graphic arts for manually cutting arounddesigns and parts of pictorial illustrations for theobject of removingsuch parts from its surroundings. One eld of use is in making separationplates, but, of course, the instrument has many other uses in thegraphic arts and elsewhere. The material cut away may be acetate sheetsor other plastic sheets, or it may be paper or Bristol board or othersuch media used in the graphic arts.

In any event, such parts, designs or the like to be cut out, andremoved, from its surroundings may be either of substantially straightlines (or partly so) or of curved lines of small or large radius ofcurvations (or partly so). The prime object of this invention is toprovide a cutting instrument of the character described which will beadapted for either rectilinear cutting (by which is meant, substantiallystraight lines) or for curvilinear cutting (by which is meant, curvedlines of varied radii of curvature). Rectilinear cutting is best done bya blade which is rigid relatively to the holder, while curvilinearcutting is facilitated by permitting the blade to rotate freely withrespect to the handle-to be,

what might be aptly termed free wheeling.

In the improved cutting instrument of this invention, means are providedfor permitting the blade to rotate freely relative to the handle.

An allied object is to provide an instrument as described which may beadjusted to provide either a rigid blade or a freely rotating blade, asdesired.

Other objects are to provide in a cutting instrument of the characterdescribed, means for readily changing blades, which means may also beused for varying the angularity of the blade, or rather its cuttingedge. A further object is to provide a cap for the blade, which cap alsofunctions in the adjusting operations (as will be described).

For the attainment of the foregoing and such other objects as may appearor be pointed out herein, I have shown a preferred embodiment of myinvention in the accompanying drawings,

wherein: K

Fig. 1 shows the complete cutting instrument of this invention, with itscap in place, the latter being cut away to reveal the blade.

Fig. 2 is an exploded view of the improved instrument of Fig. 1.

Fig. 3 is a longitudinal sectional yview through Y 2 Y the instrument,on the line 3-3 of Fig. l and on an enlarged scale.

Fig. 4 is a fragmental view, also in longitudinal section, of the endopposite the blade, showing the adjusting thimble in position changedfrom that shown in Fig. .3.

Fig. 5 is a cross-section on the line 5 5 of Fig. 3.

Fig. 6 is a cross-sectionon the line 6-5 of Fig. 1, showing a holdingpin in place.

Fig. '7 shows the blade cap partly broken away to reveal its internalserrations, and

Fig. 8 is a fragmental view, in longitudinal section, of the blade endof the instrument, showing the use of ball bearings.

The improved instrument comprises a hollow holder I, the portion thereofat the blade end (lowermost in all gures) being reduced as indicated at2, Fig. 2, a shoulder 3 being thus provided between the holder proper 4and its reduced portion 2. Reduced portion 2 is provided withlongitudinal serrations 8, Fig. 2, for frictionally holding a corksleeve 2t. Holder I is provided, as best seen in Fig. 3, with anapertured disc 6A near the blade end (lowermost in the figure) and asimilar apertured disc 'I at the other end (uppermost) both discs beingsecurely held in place.

A long slender rod II! is disposed within the hollow holder I, androtatably held in the apertured discs 6, 'I. The upper end of rod IB isthreaded at its upper end, Fig. 3, for an adjusting thimble I9, havingexternal serrations I8 toenable it to be turned by the fingers (as willbe subsequently explained). Near its lower end, rod Ill has acylindrical enlargement I6, which, as seen in Fig. 3, abuts the lowerring 6. Rod- I 0 is thusv held in place by enlargement I6 at its lowerend and by thimble I9 at its upper end.

The lowermost portion of the rod, i. e. between enlargement I6 at itslower end, is slit, as indicated at II, Fig. 3. The portion next toenlargement I Ii is threaded, while the end is slightly tapered, at I2.A small bushing 2i! is slipped on this end of rod I0 and is internallythreaded at 2|, Fig. 3, to screw on the aforesaid threads Yof rod I0.The internal diameter of bushing 20 is slightly reduced at its tip end,as indicated at 22, Fig. 3. The bushing 20 and the slitted (I I) end ofrod I0 functions as a collet to secure a very small interchangeableblade 29, or rather its reduced shank 28, see Fig. 2.

As best seen in Fig. 2, the outer surface of bushing 20 is provided withlongitudinal serrations 23, which serve a dual purpose. serrations 23provide a roughened surface enabling the fingers to turn the rathersmall bushing in making adjustments and changing the blade (as will bemore fully explained presently). The longitudinal serrations 23 of thebushing also cooperate with a small cap I4 which is placed over thebushing to cover and protect the blade when not in use. Cap I4, Which ispreferably made of a translucent plastic, such as Lucite, is providedinternally, see Fig. '7, with longitudinal serrations I3, which mateWith the external serrations 23 of bushing 20.

The thimble I9 not only serves to retain the inner rod I in place withinthehollow holder l but also functions to make the blade t28) rigid withrespect to holder l or to permit the blade to rotate freely with respectto the holder. By screwing thimble I9 down tightly, abutting Vupper discsee Fig. 4, rod I6 is held against rotation, thus maintaining knifeblade. 2Q rigid. By screwing thimble i9 to loosen it/a-s irilig, Atherod i@ is free to rotate ('in'apertured discs 6, so that the blade nowYbecomes free Wheeling (as explained in statementof invention). This endof thimble i9 is slitted at I1, Fig. 5, to receive a thin blade or theVlike for increased leverage in locking or loosening the thimble.

The blade 29 is removed or inserted by manipulation of bushing 20, asexplainedl above. During this manipulation `it is vundersi-rable thatthe inner rod l@ be free to turn. For this reason a small hole l5 isprovided diametrically through Icylindrical enlargement l6 of vthe innerrod i3.

The holder l) also has diametrically opposed apertures 5, 5, Fig. .2, asdoes 4the cork sleeve'2ll, which apertures are designated 2E, Fig. 2.When the parts are properly assembled, the hole i5 and the holderapertures 5, 5, and the cork sleeve apertures 25, 25 are aligned, asshown in Fig. 6. A pin 9 may be passed therethrough to hold the innerrod against rotation.

The bushing 2t* may then be-loosened so that the blade 2S can beremoved, or the bushing may be tightened to secure the shank 23 of theblade in collet slit Il.. These, particularly the blade and exposed endof bushing 2Q, are small parts difficult to grasp with the fingers. Butthecap la may be used for this purpose. When it is desired to loosen ortighten the bushing, cap ifi is itted in place, as shown'inFig. l. ATheYinternal serrations i3 of cap i@ interlock in the external serrations23 of bushingi! so that turning of the cap will turn the bushing.

The bearing between apertured discs 6, 1 and inner rod le may be ananti-friction or ballbearing, as is shown in Fig. 8 inconnection withthe lower bearing. The inner (smaller diameter) race IEX of theball-bearing'is secured to inner rod i0 and the outer (larger diameter)race IX is secured to the holder l.

I claim:

1. In a cutting instrumentV of the type having a holder and a blade witha reduced shank for reception in the holder, that improvement whichcomprises a hollow holder, a rod rotatably held therein, one end of saidrod being threaded and the other end being slitted, the rod beingprovided near its said slitted end with a cylindrical enlargement, athimble internally tapped for said threaded end of the rod, said thimbleserving to retain the rod in the holder, said slitted end being threadedand slightly tapered, a bushing tapped for said slitted end of the rodand slightly reduced internally near its tip end, said slitted end andsaid bushing serving as a collet to hold said blade, said thimble beingtightened to prevent rotation of the rod so that the blade is rigidrelative to the holder, and loosened to permit rotation of the rod sothat the blade is freely rotatable relative to the holder, said bushinghaving. longitudinal serrations on its outer surface, anda-caphavinginternal longitudinal serrations mating those of thev bushing so thatthe cap is friotionally retained in place and so that said cap v servesfor turning and tightening the bushing.

2. In acutgting instrument of the type having-a holder and a blade witha reduced'shank for reception in the holder, that improvement whichcomprises a hollow holder,` a rod rotatably held therein, one end ofsaid rod being threaded and the other end being slitted, the rod beingpro'- vidednear4 its said slitted end' withva cylindrical enlargement, athimble-,internally tapped for said threadedv end of therod, saidYthimble serving to retain the rod in the holder, sai-d slitted end beingthreaded, a bushing tapped ier said slitted end or the rod, saidslitted'end andrsaid bushing servingy as 'a collet trohold said blade,vsaid thimble being tightened to prevent rotation of the rod sothat theblade is rigid relative to the holder, and loosened'to permit rotationof the rod so thatthe blade isfreely rotatable relative to the holder,said lbushing having longitudinal serrations on its outer surface, saidcylindrical enlargement having a diametrically disposed hole and saidhollow holder having a pair of diametrically opposed apertures, saidhele and apert'ures being aligned 'to receive a pin toY hold the innerrod against rotation.

JOSEPH FARRIN BUNKER.

REFERENCES oiriinV The following references are of record in the

